function isNull(obj) {
    return obj === null || obj === "" || typeof obj === 'undefined' ||(obj instanceof Array && obj.length === 0 || typeof obj == "undefined");
}

function isNotNull(obj) {
    return !isNull(obj);
}

function string2Number(source) {
    if (isNotNull(source)) {
        return JSON.parse(source);
    }else{
        return source;
    }
}